Bis (perfluoroalkylmethyl) sulfites and their preparation



BIS(PERFLUOROALKYLMETHYL)SULFITES AND THEIR PREPARATION Francis E.Lawlor, Wyndmoor, Pa., assignor to Pennsalt Chemicals Corporation, acorporation of Pennsylvania No Drawing. Filed Dec. 10, 1956, Ser. No.627,140 6 Claims. (Cl. 260-456) ,bis(perfiuoroalkylmethyl) sulfite inlubricants for internal combustion engines is of value in maintainingthe component engine parts, particularly in the firing zone, in optimumcondition over prolonged periods of operation. Also,bis(2,2,2-trifluoroethyl) sulfite, especially, is a useful fumigantagainst weevils. Furthermore, the bis(perfluoroalkylmethyl) sulfites ofmy invention are bacteriostatic in activity.

The bis(perfluoroalkylmethyl) sulfites of this invention are compoundshaving the structural formula (R CH O) 80 in which Rf is aperfluoroalkyl group with l to 12 carbon atoms. A preferred compound ofthe series is bis(2,2,2- trifiuoroethyl) sulfite.

The novel compounds of my invention are prepared by reacting aperfluoroalkylmethanol having the structural formula R cH OH, in whichR; is a perfluoroalkyl group with from 1 to 12 carbon atoms, with areactant furnishing the sulfite radical, :80. The sulfite radical ispreferably supplied by a thionyl halide selected from the groupconsisting of thionyl bromide, thionyl chloride and thionyl fluoride,the thionyl chloride being preferred. The sulfite radical may also beformed in situ in the perfiuoroalkylmethanol by adding S Cl and S to thealcohol. The sulfite radical can be supplied also by reacting aperfluoroalkylmethanol with the sulfite ester of a more volatilealcohol. For example, perlluoropropylmethanol is reacted with dimethylsulfite to form bis(perfluoropropylmethyl) sulfite.

The perfluoroalkylmethanols which may be used to prepare my compoundscan be made by methods known in the art and includeperfluoromethylmethanol, perfiuoroethylmethanol,perfiuoropropylmethanol, perfiuorobutylmethanol,perfluoropentylmethanol, perfiuorohexylmethanol, and otherperfiuoroalkylmethanols with up to 12 carbon atoms in the R; group, andincluding perfiuorododecylmethanol.

In carrying out the preparation of my novel compounds, the materialfurnishing the sulfite radical is added to the perfiuoroalkylmethanol ata temperature below the boiling point of the latter compound. Theaddition may be done batchwise, or preferably, in a continuous mannerusing equipment commonly used in the art for similar United StatesPatent 0 ICC types of reactions and in a manner consistent withestablished processing precautions and operating procedures. Theconcentration of reactants may be varied over a wide range. At least astoichiometrically equivalent amount of reactant materials is requiredper mole of perfluoroalkylmethanol. For optimum yields an excess ofsulfite radical is preferably used.

In a preferred embodiment of this invention 2,2,2- trifluoroethanol isreacted with about a stoichiometrically equivalent amount of thionylchloride at a temperature in the range from about 10 C. to about C. The,

EXAMPLE 1 184 parts of 2,2,2-trifluoroethanol were mixed gradually withparts of thionyl chloride at a temperature in the range from about 20 to30 C. When the evolution of hydrogen chloride gas began, heat wasapplied. After all the thionyl chloride had been added, the mass washeated at reflux until evolution of the hydrogen chloride gas ceased.The reaction mass then was transferred to a distillation apparatus anddistilled. 91 parts of bis(2,2,2-trifiuoroethyl) sulfite were recovered,B.P. l35.5-136.5 C., n =l.336.

EXAMPLE 2 The bacteriostatic property of bis(2,2,2-trifiuoroethyl)sulfite was determined by the RDA. Phenol Coefficient Method describedin U.S.D.A. Circular No. 198, pp. 189- 196 (1941).Bis(2,2,2-trifiuoroethyl) sulfite was found effective at a 1:100dilution in water in 5 minutes against Salmonella typhosa. The phenolstandard was effective at a 1:85 dilution in the same test.Bis(2,2,2-trifiuoroethyl) sulfite is thus shown to be more effectivethan the standard.

Following procedures described in the above examples, a material ormaterials furnishing the sulfite radical, :80, preferably thionylchloride, may be used to treat a perfluoroalkylmethanol of the grouplisted in Table 1, below, to prepare the correspondingbis(perfluoroalkylmethyl) sulfite shown in the table.

Many ditferent embodiments of this invention may be made withoutdeparting from the scope and spirit of it, and it is to be understoodthat my invention includes also such embodiments and is not limited bythe above description.

structural formula (R CH O-) SO in which R is a perfluoroalkyl groupwith from 1 to 12 carbon atoms.

2 Bis'('2,2,2-trifluoroethyl) sulfite;

- 31 The process for preparing' a1 bis'( perfluoroalkyl methyl) sulfitehaving thestructural formula mcn oy so iii which' R' is a perfluoroalkylgroup with from I to 1-2 carbon atoms, which comprises reactingia"perfluoroalkylmethanol having the structural formula R CHOH, in

thionyl fluoride.

4.-The process for'preparation' of bis(2,2,2-trifiuoro=- r'thanolwith athionyl halide selected from the I group =con-" sisting of thionylbromide, thionylchloride and thionyl SPThe process. for preparation ofbis(2,2",2-trifluoro"- ethyl) sulfite which comprises reacting2,2,2-trifluoro ethanolin about a* stoichiometrica'lly equivalent amountwith a thionyl halide selected from the group consisting of thionylbromide, thionyl chloride and thionyl fluoride.

6. The process for preparation of bis(2,2,2-trifiuoroethyl) sulfitewhich comprises reacting 2,2,2-trifiuoroethanol in about astoichioniet'r'ically equivalent amount with thionyl chloride at atemperature from about-20 C; to" about the boiling point of the"reaction rn'as'S'.

ReferencesCited in the file of thispatent UNITED STATES PATENTSMikeskaet al.- Jan. 7, 1958 OTHER REFERENCES Olah et al.: Chem. Ab.,vol. 49, May 1955, pp.

Henne et al.: J.A.C.-S. 70, p; 1968 (1948). p Cook; Progress in OrganicChemistry; vol; 2, pp; 59 61 ("I -9 53*).

1. A BIS(PERFLUOROALKYLMETHYL) SULFITE HAVING THE STRUCTURAL FORMUAL(R1CH2O)2SO IN WHICH R1 IS A PERFLUOROALKYL GROUP WITH FROM 1 TO 1ICARBON ATOMS.